1) Four species of liverworts have aseptically been cultivated over four years on an agar medium (MSK-3) containing only mineral salts (no organic nutrients). The cultivation induced the following morphological modifications. 2) Haplomitrium mnioides. Leaves are distinctly incised as in H. hookeri. 3) Trichocolea tomentella. Plants are extremely small and often at the stage of protonema. Stems are of only 6 cell rows at most and have no branchings of the Frullania-type. Leaves and underleaves are deeply 1-3-furcate or -ternate, and their laminae are vestigial. 4) Calypogeia tosana. The following various forms were obtained (mentioned in order of frequency) : (i) a form similar to the wild type ; (ii) a form with young buds in almost every underleaf-axil ; (iii) a form with leaves which are dorsally second and concave ; (iv) a form with under leaves as large as leaves ; (v) a form with small underleaf-like leaves ( in one row), the large, normal-shaped leaves (in another row), and large, leaf-like underleaves ; (vi) a form partially with large "dorsal" leaves and without underleaves ; and (vii) a form partially with large dorsal leaves which are sporadically united with the adjacent leaves. 5) Ptychanthus striatus. Plants are very small and have no branchings of the Frullania-type. Leaf-lobes and underleaves are quite or nearly entire (not dentate as in the wild type), and leaf-lobules are often strongly inflated. Underleaves are often doubled in number in the basal part of a small shoot. 6) All species show a wide range of variation in some characters (especially, in the size of plants and the shape of leaves and underleaves) even among individuals growing side by side in the same flask. The character of cells (cell-walls, chloroplasts and oil-bodies) is rather stable and little deviated from the wild type. 7) In Haplomitrium mnioides, the marginal tooth of a leaf is always tipped with a slime papilla. This papilla is found not only in the cultured form with incised leaves but also in the wild form with entire leaves- 2-4 slime papillae are always present along the leaf margin of the latter. The papillae are also scattered on the stem surfaces of both erect, leafy branches and leafless stolons. This suggests that the papillae of the Calobryales are homologous with those of the Metzgeriales and the leaves of the former with the ventral scales of the latter.
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